Sulfidation of zinc oxide sorbent by desulfurization of steam-hydrogasifier product gas was affected by non-steam components of the reactant gas in a complicated manner. Relative abundance of each component appeared to shift the reaction equilibrium toward ZnO sulfidation, thereby enhancing the extent of sorbent utilization for sulfur removal, while their respective contributions were not simply additive toward the overall increase of sulfur capture capacity of the sorbent. This subtle outcome will have to be further investigated by varying, respectively, the individual abundance of each non-steam component as well as H2S content of the reactant gas to be desulfurized.